If I do manual summarization on a single interface of a class b address, will eigrp still advertise my other class c networks out that interface? In other words, will summarization leave the rest of the routing table intact?
also, can I manually summarize on the real interfaces if I'm using hsrp?
EIGRP will send out the interface where the interface is configured the /16 and will suppress all subnets within the summary address IP block.
Other IP subnets out of the summary will not be affected.
Notice that if needed you can configure multiple summaries if needed.
HSRP config is not an issue and will be used by devices not running EIGRP (so I hope ) to provide a default gateway or a next hop for static routes.
Be aware that if the routers are two (HSRP implies this) if you configure the summary on only one router the other router will be preferred for destinations within the summary because it provides more specific routes
Hope to help